This invention refers to an ultrasonic measurement system for determining the density and structure of bone.
There are known electronic systems for determining bone density, equipped with a first ultrasonic transducer designed to send multiple impulses into a body segment under examination (for example, a finger) and a second transducer designed to detect the impulses that actually pass through that body segment.
The known systems are further equipped with computer circuits that calculate the time elapsing between the emission of the impulse by the first transducer and its detection, and which calculate, on the basis of the known distance between the transducers, the velocity with which the ultrasounds pass through the body segment under examination.
The transmission velocity of the ultrasound signal is strongly influenced by the characteristics of the bone tissue placed between the transducers and varies with the variations in bone structure and density.
The known systems therefore compare the value of the measured velocity with a reference value, for the purpose of detecting a variation in the structure and density of the bone, which normally indicates decalcification of the bone tissue (caused, for example, by osteoporosis).
Comparison between the measured value and the reference value is not always adequate to permit an accurate examination, because the velocity with which the ultrasounds are transmitted through the tissue varies strongly from one subject to another or in a single subject if the measurement sites cannot be located repeatedly with great accuracy.
For this reason, the known systems do not permit an accurate or, especially, a reproducible examination.